Unity has many useful assets that make your indie game developer journey become more easier. I have already invested in some several assets to make my own game. The problem is, some of them really have big in size. More, the asset store downlink is very frustating, it really slow and take along time to finish download.
This unofficial trick can be used to download unity asset outside unity assetstore using download manager or via browser. So you can resume your download when you have really unstable connection.
WARNING!!! Do it at your own risk.
In this case, i will download Third Person Controller as example.
You need to download Hex Editor. You can use any hex editor, but i use this free Hex Editor: HxD
Step by Step
As you can see, it has 461.8 MB in size. It really big size and can trouble you if you had unstable connection.
Start download, and it will create a temp file at: C:\Users\[User]\AppData\Roaming\Unity\Asset Store-5.x\[Asset Store File]
[User] : Change your user name
[Asset Store File] : Name of respected unity package. (Unity Asset Store Developer-Category-Asset File Name)
Copy .json file to another folder. And quit Unity.
Inside .json file you will find the download link that can be resumed using your favorite download manager!
After you have finished, rename the file to the same name as json file (without .json).
Make a backup of .tmp file and edit using HxD you have downloaded using link above. The downloaded asset is still encrypted.
Now you need to delete one bytes or more.
This will allow Unity to decrypt asset package without error.
In this my case, i deleted two bytes at the end of the file.
Save the file.
Now, copy back modified .tmp and .json file to C:\Users\[User]\AppData\Roaming\Unity\Asset Store-5.x\[Asset Store File] again,
Open Unity and download the asset again. Your download will immediately finish. And unity will decrypt the file. If you lucky you can then import the file and use it. If the decryption error, repeat edit file using Hex editor part and try it again.
Good luck :)